Process for producing a colorless mineral oil having good hazing properties

ABSTRACT

The process comprises contacting a mineral lubricating oil distillate with a first hydrogenation catalyst in a first hydrogenation reaction zone to obtain a first hydrogenated product; subjecting said first hydrogenated product to a solventdewaxing treatment to obtain a dewaxed, hydrogenated product; contacting said dewaxed, hydrogenated product consecutively with a second hydrogenation catalyst in a second hydrogenation reaction zone and a third hydrogenation catalyst in a third hydrogenation reaction zone. The contacting in each hydrogenation zone is carried out under selected hydrogenation conditions and in the presence of hydrogen. The first hydrogenation catalyst and second hydrogenation catalyst each comprise a metal of Group VIII and a metal of Group VIB on a non-acidic or weakly-acidic support, while the third hydrogenation catalyst comprises a Group VIII noble metal on a suitable support. The improvement of subjecting the first hydrogenated product to a solvent-dewaxing treatment prior to the subsequent hydrogenation treatments provides a colorless mineral oil having good hazing properties.

United States Patent Menzl Dec. 16, 1975 PROCESS FOR PRODUCING A COLORLESS MINERAL OIL HAVING GOOD-HAZING PROPERTIES Primary Examiner-Herbert Levine Attorney, Agent, or FirmJames L. Wilson; Arthur G. Gilkes; William T. McClain [57] ABSTRACT The process comprises contacting a mineral lubricating oil distillate with a first hydrogenation catalyst in a first hydrogenation reaction zone to obtain a first hydrogenated product; subjecting said first hydrogenated product to a solvent-dewaxing treatment to obtain a dewaxed, hydrogenated product; contacting said dewaxed, hydrogenated product consecutively with a second hydrogenation catalyst in a second hydrogenation reaction zone and a third hydrogenation catalyst in a third hydrogenation reaction zone. The contacting in each hydrogenation zone is carried out under selected hydrogenation conditions and in the presence of hydrogen. The first hydrogenation catalyst and second hydrogenation catalyst each comprise a metal of Group VIII and a metal of Group VIB on a non-acidic or weakly-acidic support, while the third hydrogenation catalyst comprises a Group V111 noble metal on a suitable support.

The improvement of subjecting the first hydrogenated product to a solvent-dewaxing treatment prior to the subsequent hydrogenation treatments provides a colorless mineral oil having good hazing properties.

19 Claims, 1 Drawing Figure FEED BLEND 1st REACTION ZONE SOLVENT- DEWAXING ZONE 2nd REACT ION ZONE 3rd REACTION HAZE FREE PRODUCT FEED BLEND h ll lsi REACTION \IZ ZONE soLvENT- DEWAXING ZONE and R EACT ION l6 ZONE 3rd REACTION \la ZONE HAZE FREE PRODUCT PROCESS FOR PRODUCING A COLORLESS MINERAL OIL HAVING GOOD HAZING PROPERTIES BACKGROUND OF THE INVENTION many cases, the feedstock had been dewaxed and/or solvent extracted. Such finishing treatments provided a treated product that possessed improved color and odor and, in many cases, improved stability to light and oxidation. In general, stability to oxidation and to light has been maintained by the addition of one or more chemicals to the finished product. In recent years, the quality of lubricating oils has been improved by a finishing treatment comprising a relatively severe hydrogenation treatment.

One of the important applications of hydrotreating a lubricating oil distillate is the hydrotreating of mineral oils to produce white oils. A white oil is a highly refined lubricating oil fraction which has a colorless, water-white appearance. Such an oil must be colorless, odorless, and tasteless; and it must be essentially free of aromatic hydrocarbons. It must have a color of Saybolt and must possess a low absorbence of ultraviolet light. Typical white oils may be used for cosmetics and certain medicinal purposes.

The hydrogenation treatment of a lubricating oil fraction to produce a white oil, in general, comprises a twostage process. In the first stage of a typical process, the selected lubricating oil fraction is desulfurized over a sulfactive hydrogenation catalyst under relatively severe hydrogenation conditions, and the liquid effluent from this first stage is contacted in a second stage with hydrogen under relatively mild conditions with a hydrogenation catalyst comprising a platinum group metal on a non-acidic or a weakly-acidic support. In some instances, the above two-stage process must be preceded by a mild-hydrogenation step to help reduce the sulfur content of the mineral lubricating oil distillate being treated. Often, the hydrotreated product resulting from such a three-stagehydrogenation process does not possess good hazing properties, i.e upon standing, the product contains a haze.

The improved process of the present invention has three hydrogenation steps, but provides a product that has good hazing properties. The product does not contain haze; nor does a haze appear after the product has been standing for a period of time. Moreover, the product passes the Solid Paraffin Test that is described in both the Regulations for Mineral Oil in the UNITED STATES PI-IARMACOPEIA XVIII (1970), pp. 436437, and the Regulations for Light Mineral Oil in the NATIONAL FORM ULARY XIII 1970), pp. 461-462.

SUMMARY OF THE INVENTION hydrogen to obtain a first hydrogenated produ'cfisubjecting said first hydrogenated product to a solventdewaxing treatment to obtain a dewaxed, hydrogenated product; contacting said dewaxed, hydrogenated 'product with a second hydrogenation catalyst in a second hydrogenation reaction zone under second hydrogenation conditions and in the presence of hydrogen to obtain a second hydrogenated product; and contacting said second hydrogenated product with a third hydrogenation catalyst in a third hydrogenation reaction zone under third hydrogenation conditions and in the presence of hydrogen to obtain said colorless mineral oil. The distillate may be a solvent-extracted distillate or a solventextracted and dewaxed distillate.

The various hydrogenation conditions that are employed in this process are selected conditions and are described hereinafter.

The first hydrogenation catalyst and second hydrogenation catalyst each comprises a metal of Group VIII of the Periodic Table of Elements and a metal of Group VIB of the Periodic Table of Elements on a non-acidic or weakly-acidic support. The preferred Group VIII metals are cobalt and nickel, while the preferred'Group VIB metal is molybdenum. The preferred support is a catalytically active alumina.

The third hydrogenation catalyst comprises a Group VIII noble metal on a non-acidic or weakly-acidic support. The preferred Group VIII noble metal is palladium and the preferred support is a large-pore-diameter alumina.

The preferred solvent-dewaxing treatment employs a solvent comprising a mixture of an aromatic hydrocarbon and a ketone, e.g., a mixture of toluene and methyl-ethyl ketone. Typically, the solvent-to-hydrocarbon ratio that is employed in the solvent-dewaxing treat BRIEE DESCRIPTION OF THE DRAWING The accompanying FIGURE represents a very simplified flow scheme of a preferred embodiment of the improved process of the present invention.

DESCRIPTION OF THE INVENTION According to the present invention, there is provided a process for producing a colorless mineral oil having good hazing properties. This process comprises contacting a mineral lubricating oil distillate with a first hydrogenation catalyst in a first hydrogenation reaction zone under first hydrogenation conditions and in the presence of hydrogen to obtain a first hydrogenated product; subjecting said first hydrogenated product to a solvent-dewaxing treatment to obtain a dewaxed, hydrogenated product; contacting said dewaxed, hydrogenated product with a second hydrogenation catalyst in a second hydrogenation reaction zone under second hydrogenation conditions and in the presence of hydrogen to obtain a second hydrogenated product; and contacting'said second hydrogenated product with a third hydrogenation catalyst in a third hydrogenation reaction zone under third hydrogenation conditions and in the presence of hydrogen to obtain a third hydrogenated product, which is said colorless mineral oil.

It is to be understood that the effluent from each hydrogenation reaction zone undergoes appropriate liquid-gas separation techniques well-known to those skilled in the art in order to separate any gaseous material or normally vaporous material from the liquid product that is obtained from that particular hydrogenation reaction zone. The liquid product is referred to herein as hydrogenated product. Of course, substantially all of the hydrogen sulfide and ammonia formed in that particular hydrogenation reaction zone is separated from the liquid product during such liquid-gas separation.

While there are processes available to provide colorless mineral oils, which processes employ two or three hydrogenation steps, many furnish a product that has poor hazing properties. For example, initially the product'may possess a haze or a haze may form upon standing. The product obtained from the process of the present invention has good hazing properties. It does not have a haze originally, and a haze does not form upon standing-x Y The improvement of the process of the present invention comprises subjecting the first hydrogenated product to a solvent-dewaxing treatment prior to contacting it with said second hydrogenation catalyst in said second hydrogenation reaction zone. During the first hydrogenation step, wherein the mineral lubricating oil distillate is contacted with a first hydrogenation catalyst in a first hydrogenation reaction zone, the distillate is desulfurized. Most of the desulfurization occurs in this reaction zone. The distillate feed may contain sulfur in an amount ranging from about 0.1 to about 1 weight percent. The hydrogenated product coming from this first hydrogenation reaction zone probably will contain a sulfur level of about 0.005 to 0.5 weight percent sulfur. While the sulfur level is being reduced by this first hydrogenation treatment, some hydrocracking occurs in the reaction zone and a, certain amount of paraffins forms, which paraffins may producehaze or contribute to the formation of haze in the final or finished product of the process. Although it is not known what actually takes place, it is theorized that additional'paraffinic materials may be formed during the removal of sulfurv from the thiophenic ring compounds. However, it is to be understood that such theory is presented for its informational value only and is, in no way, intended to limit the scope of the present invention. Since, in the' subsequent hydrogenation steps, additional paraffins may be formed, such additional paraffins, when combined with those already present in the first hydrogenated product, may provide a sufficient amount of paraffins to product the haze in the finished product or may lead to the appearance of haze upon standing. When the first hydrogenated product is subjected to a solvent-dewaxing treatment, a substantialamount of the paraffins formed during the first hydrogenation step are removed therefrom. Any additional paraffins formed in the subsequent hydrogenation steps, when coupled with any remaining paraffins in the first hydrogenated product, will not provide a total amount of paraffins that will be sufficient to result in the formation of a haze in the final product.

The solvent-dewaxing treatment that is used in the process of the present invention employs a solvent that will facilitate the separation of waxy substances and haze formingbodies, such as paraffins, from the mineral oil being treated. Suitably, such solvent comprises a mixture of an aromatic hydrocarbon and a ketone.

Preferably, the solvent is a mixture of toluene and methyl-ethyl ketone. Such a mixture will contain from about 30 percent to about 60 percent toluene. Typically, the solvent-to-hydrocarbon ratio that is employedin the solvent-dewaxing treatment of the process of the present invention ranges from about 1:1 to about 4:1. Preferably, the ratio is at least 2.4: 1.

Any minerallubricating oil distillate may be treated in the process of the present invention. The feedstock might be a light lubricating oil, or it could be a heavy lubricating oil. The viscosity of the oil could have a value as low as about 40 Saybolt seconds at F. On the other hand, the feedstock can'have a viscosity as high as an SAE-6O material. Preferably, the distillate will have a viscosity at 100F. of about 200 SUS to about 1,000 SUS. Generally, the feedstock to the process of the present invention is a solvent-extracted material or a solvent-extracted and dewaxed mineral lubricating oil distillate. Solvents that may be used for the solvent-extraction of such a feedstock include phenols, furfurals, liquid S0 nitrobenzene, and dimethyl formamide.

The catalyst that is employed in the first hydrogenation reaction zone, i.e., the first hydrogenation catalyst, is a sulfactive hydrogenation catalyst. It is contemplated, according to the present invention, that such sulfactive hydrogenation catalyst may comprise a metal of Group VIII of the Periodic Table of Elements and a metal of Group VIB of the Periodic Table of Elements deposed on a non-acidic or weakly-acidic catalyst support. Such supports include catalytically active alumina, silica, and activated carbon. The Periodic Table of Elements consulted is the Periodic Table that is found on page 628 of WEBSTERS SEVENTH NEW COLLEGIATE DICTIONARY, G. and C. Merriam Company, Springfield, Mass. U.S.A., 1963. Typical Group VIII metals are cobalt and nickel. A typical Group VIB metal is molybdenum. These typical metals are the preferred metals that are employed in the first hydrogenation catalyst that is used in the process of the present invention. The metals of this first hydrogenation catalyst are present in the elemental form, as the oxides of the metals, as the sulfides of the metals, or as mixtures thereof. The Group VIII metal may be present in an amount of about 0.5 to about 5 weight percent, while the Group VIB metal may be present in an amount of about 5 to about 25 weight percent, each metal being calculated as the oxide and based on the total weight of the catalytic composition.

The second hydrogenation catalyst of the process of the present invention may be the same as the first hydrogenation catalyst. That is, the second hydrogenation catalyst comprises a metal of Group VIII of the Periodic Table of Elements and a metal of Group VIB of the Periodic Table of Elements deposed on a suitable non-acidic or weakly-acidic support.

The support of either the first hydrogenation catalyst or the second hydrogenation catalyst is a suitable nonacidic or weakly-acidic support, such as a refractory inorganic oxide. Suitable supports are a catalytically active alumina, silica, or activated carbon. Preferably, the support is a catalytically active alumina. Such catalytically active alumina may have an average pore diameter of about 50 Angstrom units (A) to about 200 A, or even greater. The surface area of this catalytically active alumina should be within the range of about 100 square meters per gram to about 800 square meters per gram, or larger.

The third hydrogenation catalyst of the process of the present invention is a catalyst which comprises a Group VIII noble metal on a suitable non-acidic or weaklyacidic support. The support may be a catalytically active alumina, silica, or activated carbon. The Group VIII noble metal may be palladium, platinum, rhodium, iridium, ruthenium, or osmium. The preferred Group VIII noble metal is palladium. The Group VIII noble metal may be present in an amount of about 0.1 to about 2 weight percent, calculated as the element and based on the total weight of the catalytic composition.

The preferred support material for the third hydrogenation catalyst is a large-pore-diameter alumina. The average pore diameter of such alumina should be within the range of about 100 A to about 200 A. Suitably, the average pore diameter should be at least 120 A. Preferably, the average pore diameter of the alumina that is employed in the third hydrogenation catalyst is at least 130 A. The surface area of this largepore-diameter alumina should be within the range of about 150 square meters per gram to about 500 square meters per gram. Suitably, the surface area is at least 200 square meters per gramv Preferably, the surface area is at least 300 square meters per gram.

The catalysts that are employed in the process of the present invention may also contain minor amounts of other components which do not adversely affect the performance of the catalyst for the hydrogenation and finishing of mineral lubricating oil distillates. An example of such a component is silica, which may be present in an amount of no more than 4 weight percent, preferably less than 2 weight percent, and which may provide a stabilizing effect upon the particular catalyst.

The catalytic compositions that are employed in the process of the present invention may be prepared by various methods. For example, the hydrogenation metals may be added in the form of soluble salts to either a hydrosol or hydrogel of the refractory inorganic oxide that is being employed as the support material. The resulting composite is subsequently blended, dried, and calcined. In the case of the first hydrogenation catalyst and the second hydrogenation catalyst, the two hydro genation metals may be added simultaneously or sequentially. As an alternative, either extrudates or pellets of the refractory inorganic oxide support may be impregnated with one or more aqueous solutions of the hydrogenation metals being incorporated onto the support material. The impregnated composite may then be dried and calcined.

According to the present invention, there is provided a process for the production of a colorless mineral oil. The mineral lubricating oil distillate that is being treated by this process is first contacted with a first hydrogenation catalyst in a first hydrogenation reaction zone under first hydrogenation conditions and in the presence of hydrogen to produce a first hydrogenated product. Primarily, hydrogenation and desulfurization occur in the first hydrogenation reaction zone. The first hydrogenation conditions comprise a hydrogen partial pressure of about 400 to about 2,000 psia, a temperature of about 550F. to about 800F., a liquid hourly space velocity (LHSV) of about 0.25 to about 5 volumes of hydrocarbon per hour per volume of catalyst, and a hydrogen circulation rate of about 200 to about 5,000 standard cubic feet of hydrogen per barrel of hydrocarbon (SCFB). Preferably, the first hydrogenation conditions comprise a hydrogen partial pressure of about 650 to about 1.200 psia, a temperature of about 6 600F. to about 700F., a LHSV of about 0.25 to about 1.5 volumes of hydrocarbon per hour per volume of catalyst, and a hydrogen circulation rate of about 300 to about 1,200 SCFB.

The first hydrogenated product is subjected to a solvent-dewaxing treatment which is discussed hereinabove to provide a dewaxed, hydrogenated product. The dewaxed, hydrogenated product is then contacted with a second hydrogenation catalyst in a second hydrogenation reaction zone under second hydrogenation conditions and in the presence of hydrogen. The second hydrogenation conditions comprise a hydrogen partial pressure of about 800 to about 5,000 psia, a temperature of about 600F. to about 1,000F., a LHSV of about 0.1 to about 5 volumes of hydrocarbon per hour per volume of catalyst, and a hydrogen circulation rate of about 1,000 to about 25,000 SCFB. Preferably, the second hydrogenation conditions comprise a hydrogen partial pressure of about 1,600 to about 3,600 psia, a temperature of about 650F. to about 800F., a LHSV of about 0.2 to about 1 volume of hydrocarbon per hour per volume of catalyst, and a hydrogen circulation rate of about 4,000 to about 12,000 SCFB. A second hydrogenated product is obtained from the second hydrogenation reaction zone.

The second hydrogenated product is subsequently contacted in a third hydrogenation reaction zone with a third hydrogenation catalyst under third hydrogenation conditions and in the presence of hydrogen to provide the desired colorless mineral oil. The third hydrogenation conditions comprise a hydrogen partial pressure of about 500 to about 3,000 psia, a temperature of 450F.

to 500F., a LHSV of about 0.1 to about 1 volume of hydrocarbon per hour per volume of catalyst, and a hydrogen circulation rate of about 1,500 to about 15,000 SCFB. Preferably, the third hydrogenation conditions comprise a hydrogen partial pressure of about 1,000 to about 2,500 psia, a temperature of 450F. to 500F., a LHSV of about 0.25 to about 0.6 volume of hydrocarbon per hour per volume of catalyst, and a hydrogen circulation rate of about 5,000 to about 10,000 SCFB.

As pointed out hereinabove, the sulfur concentration of the mineral lubricating oil distillate that is employed as a feedstock is reduced in the first hydrogenation reaction zone to a sulfur content of about 0.005 to about 0.5 weight percent sulfur. Preferably, the sulfur content is reduced to a level of about 0.01 to about 0.4 weight percent sulfur in the first hydrogenation reaction zone. The dewaxed, hydrogenated product is sent to the second hydrogenation reaction zone and the sulfur content is reduced further to a level that is less than 10 parts per million sulfur, preferably, less than 1 part per million sulfur.

The product that is obtained from the process of the present invention is a colorless, water-white oil and has a color of +30 Saybolt and possesses a low absorbence of ultraviolet light. The UV analysis, pursuant to the Food and Drug Administration specification, can have a maximum value of 0. 1. The product, when submitted to the test for readily carbonizable substances can have a maximum USP-Acid Test value of 2.5. In addition, the product must have good hazing properties. The product must be free of haze and upon standing must remain free of haze. As pointed out hereinabove, the haze properties may be determined by the Solid Paraffin Test that is described in both the Regulations for Mineral Oil in the UNITED STATES PHARMACO- 7 PEIA XVIII (1970), pp. 436-437, and the Regulations for Light Mineral Oil in the NATIONAL FORMU- LARY XIII (1970), pp. 461-462.

The accompanying figure presents a very simplified schematic representation of a preferred embodiment of the improved process of the present invention. The various pumps, compressors, heaters and heatexchange equipment, liquid-gas separators, strippers, recycle-gas equipment, and the like are not shown, since their use and position in such a hydrofinishing process are well known to those skilled in the art.

In this preferred embodiment of the process of the present invention, as shown in the figure, a blend of a solvent-extracted SAE-40 oil and a solvent-extracted SAE-20 oil is passed via line 11 into a first hydrogenation reaction zone 12, where it is contacted with a catalyst comprising about 3 weight percent cobalt oxide and about weight percent molybdenum trioxide on a catalytically active alumina. The catalyst is present in one or more fixed beds. The hydrogenation conditions in first hydrogenation reaction zone 12 are the same as those discussed hereinabove. The blend of solvent-extracted material is made up of about 2 parts of SAE-4O oil to 1 part SAE- oil. Hydrogen or hydrogen-containing gas is added to first hydrogenation reaction zone 12 and the operating conditions are such that desulfurization takes place. The sulfur level of the feedstock, which may be somewhere between 0.1 and 1 weight percent sulfur, is reduced to a level of about 0.005 to about 0.5 weight percent sulfur. This hydrogenated product is then passed via line 13 to a solventdewaxing zone 14, where it is subjected to a solventdewaxing treatment.

The solvent employed in the solvent-dewaxing treatment is a mixture of toluene and methyl-ethyl ketone. It contains 45 percent toluene and 55 percent methylethyl ketone. The ratio of solvent-to-hydrocarbon is at least 2.4:].

The resulting dewaxed, hydrogenated product is then passed via line 15 into a second hydrogenation reaction zone 16 and contacted with a second hydrogenation catalyst under second hydrogenation conditions as are discussed hereinabove. The second hydrogenation catalyst comprises about 3 weight percent nickel oxide and about 15 weight percent molybdenum trioxide on a catalytically active alumina and is present in one or more fixed beds. The second hydrogenated product, which is the effluent from second hydrogenation reaction zone 16, has a sulfur level that is less than 10 parts per million sulfur, preferably, less than 1 part per million sulfur.

In the case of the effluent from first hydrogenation reaction zone 12 and the effluent from second hydrogenation reaction zone 16, each is separated into a liquid product and a gaseous product, the latter of which contains any hydrogen sulfide and ammonia that would be formed during the particular hydrogenation treatment.

The desulfurized second hydrogenated product, essentially free of hydrogen sulfide and ammonia, is then passed via line 17 into a third hydrogenation reaction zone 18 and is contacted with a third hydrogenation catalyst comprising 0.5 weight percent palladium supported on a large-pore diameter alumina. This largepore-diameter alumina may have values for its surface area and its average pore diameter as described hereinabove.

The operating conditions, that is, the third hydrogenation conditions, employed in third hydrogenation reaction zone 18 are as described hereinabove. The effluent from third hydrogenation reaction zone 18 is removed therefrom via line 19 and is treated to remove the gaseous material from the liquid effluent.

The liquid product, that is, the hydrotreated mineral lubricating oil distillate, possesses a Saybolt color of +30, a USP-Acid Test value that is no greater than 2.5 and a FDA-UV Absorbence value that is no greater than 0.1, and is haze free. Moreover, upon standing, this product remaing haze free.

It is to be understood that the above preferred embodiment and the following examples are presented for purposes of illustration only and are not intended to limit the scope of the present invention, which invention is defined by the claims appended hereto.

EXAMPLE I A typical embodiment of the process of the present invention was conducted in commercial equipment. The feedstock that was treated was a blend of about 35 percent SAE-20 raffinate and about 65 percent SAE- 40 raffinate.

This feedstock was hydrotreated in a first hydrogenation reaction zone in the presence of a catalyst comprising the oxides of cobalt and molybdenum on alumina. This catalyst was employed as 1/16-inch pellets and was made up of 26 percent Nalco 471 catalyst, manufactured by the Nalco Chemical Company, and 74 percent HDS-2A catalyst, manufactured by the American Cyanamid Company. the hydrogenation conditions in this first hydrogenation reaction zone were an inlet temperature of 680F., an outlet temperature of 700F., a feed rate of 120 barrels per hour accompanied by a quench rate of 4 barrels per hour, a hydrogen partial pressure of about 800 psia, a LHSV of about 0.57 volume of hydrocarbon per hour per volume of catalyst, and a hydrogen circulation rate of about 512 SCFB.

The effluent obtained from the first hydrogenation reaction zone was treated to separate the gaseous material from the liquid hydrogenated and desulfurized product, which was dewaxed in a dewaxing unit employing methyl-ethyl ketone and toluene as the dewaxing solvent. The dewaxed material had a viscosity at F. of 580 SUS and a viscosity at 210F. of 66.1 SUS. The viscosity index was 89.5. The Pour Point of this material was 10F. The refractive index was 1.4516 and the ASTM color was 1 to 1 /2.

The dewaxed, hydrogenated distillate was then contacted in a second hydrogenation reaction zone with a second hydrogenation catalyst comprising HDS-3A catalyst manufactured by the American Cyanamid Company. This catalyst comprised about 3 weight percent nickel oxide and 15 weight percent molybdenum trioxide on a catalytically active alumina support. The hydrogenation conditions employed in this second hydrogenation reaction zone were a temperature of 690F., a hydrogen partial pressure of about 2,600 psia, a Ll-ISV of 0.27 volume of hydrocarbon per hour per volume of catalyst, and a hydrogen circulation rate of about 11,550 SCFB.

After the gaseous material was separated from the liquid product obtained from the second hydrogenation reaction zone, the liquid product was then hydrogenated in a third hydrogenation zone. The third hydrogenation reaction zone was operated at a temperature of 475F., a hydrogen partial pressure of about 1,600 psia, a LHSV of 0.25 volume of hydrocarbon per hour per volume of catalyst, and a hydrogen circulation rate of about 6,900 SCFB. There was used in the third hydrogenation reaction zone a catalyst comprising 0.5 weight percent palladium on a large-pore-diameter alumina. This alumina had a surface area of about 214 square meters per gram and an average pore diameter of about 1 A. The effluent from the third hydrogenation reaction zone was separated into gaseous material and liquid product.

The liquid product, a colorless, water-white mineral oil that was obtained from the third hydrogenation reaction zone, possessed a viscosity of about 355 to about 390 SUS at 100F. It not only passed the Solid Paraffin Test, but also was completely clear at th end of the test. Upon standing, no haze was formed in the liquid product obtained from the process.

EXAMPLE II An example of a typical prior-art process treated a blend of a dewaxed SAE- raffinate and a hydrotreated SAE-4O raffinate, which had been dewaxed, prior to being hydrotreated. This blend was composed of about 35 percent SAE-20 material and about 65 percent SAE-40 material. The conditions employed for the hydrotreating of the dewaxed SAE-40 raffinate were an inlet temperature of about 620F., a hydrogen partial pressure of about 800 psia, a LHSV of about 0.95 volume of hydrocarbon per hour per volume of catalyst, and a hydrogen circulation rate of about 400 SCFB.

The blend was then hydrotreated sequentially in a second hydrogenation reaction zone and a third hydrogenation reaction zone. The operating conditions in each of these latter two reaction zones were the same as those employed in the corresponding reaction zones of the embodiment of the process of the present invention presented in Example I hereinabove.

The liquid product obtained from the third hydrogenation reaction zone in the process of this example failed the Solid Paraffin Test.

What is claimed is:

l. A process for producing a colorless mineral oil having good hazing properties from a mineral lubricating oil distillate, which process comprises contacting said distillate with a first hydrogenation catalyst comprising a metal of Group VIB of the Periodic Table of Elements and a metal of Group VIII of the Periodic Table of Elements deposed on a non-acidic or weaklyacidic support in a first hydrogenation reaction zone under first hydrogenation conditions and in the presence of hydrogen to obtain a first hydrogenated product; subjecting said first hydrogenated product to a solvent-dewaxing treatment to obtain a dewaxed, hydrogenated product; contacting said dewaxed, hydrogenated product with a second hydrogenation catalyst comprising a metal of Group VIB of the Periodic Table of Elements and a metal of Group VIII of the Periodic Table of Elements deposed on a non-acidic or weaklyacidic support in a second hydrogenation reaction zone under second hydrogenation conditions and in the presence of hydrogen to obtain a second hydrogenated product; and contacting said second hydrogenated product with a third hydrogenation catalyst comprising a Group VIII noble metal deposited on a non-acidic or a weakly-acidic support in a third hydrogenation reaction zone under third hydrogenation conditions and in 10 the presence of hydrogen to obtain said colorless mineral oil, said metals of said first hydrogenation catalyst and said metals of said second hydrogenation catalyst being present in the elemental form, as the oxides thereof, as the sulfides thereof, or as mixtures thereof.

2. The process of claim 1 wherein said distillate is a solvent'extracted mineral lubricating oil distillate.

3. The process of claim 1 wherein said distillate is a solvent-extracted and dewaxed mineral lubricating oil distillate.

4. The process of claim 1 wherein said first hydrogenation conditions comprise a hydrogen partial pressure of about 400 to about 2,000 psia, a temperature of about 550F. to about 800F., a LI-ISV of about 0.25 to about 5 volumes of hydrocarbon per hour per volume of catalyst, and a hydrogen circulation rate of about 200 to about 5,000 SCFB; said second hydrogenation conditions comprise a hydrogen partial pressure of about 800 to about 5,000 psia, a temperature of about 600F. to about 1,000F., a LHSV of about 0.1 to about 5 volumes of hydrocarbon per hour per volume of catalyst, and a hydrogen circulation rate of about 1,000 to about 25,000 SCFB; and said third hydrogenation conditions comprise a hydrogen partial pressure of about 500 to about 3,000 psia, a temperature of 450F. to 500F., a LSI-IV of about 0.1 to about 1 volume of hydrocarbon per hour per volume of catalyst, and a hydrogen circulation rate of about 1,500 to about 15,000 SCFB.

S. The process of claim 2 wherein said solventextracted mineral lubricating oil distillate is a blend of a solvent-extracted SAE-4O oil and a solvent-extracted SAE-2O oil.

6. The process of claim 1 wherein said first hydroge nation catalyst and said second hydrogenation catalyst each contains about 0.5 to about 5 weight percent Group VIII metal and about 5 to about 25 weight percent Group VIB metal, calculated as the oxides and based on the total weight of the particular catalyst, and said third hydrogenation catalyst contains about 0.1 to about 2 weight percent Group VIII noble metal, calculated as the element and based on the total weight of said third hydrogenation catalyst.

7. The process of claim 4 wherein said distillate is a solvent-extracted mineral lubricating oil distillate.

8. The process of claim 6 wherein said first hydrogenation catalyst and said second hydrogenation catalyst each comprise nickel and molybdenum on alumina and said third hydrogenation catalyst comprises palladium on a large-pore-diameter alumina havng a surface area of about 150 square meters per gram to about 500 square meters per gram and an average pore diameter of about A to about 200 A.

9. The process of claim 6 wherein said first hydrogenation conditions comprise a hydrogen partial pressure of about 400 to about 2,000 psia, a temperature of about 550F. to about 800F., a LHSV of about 0.25 to about 5 volumes of hydrocarbon per hour per volume of catalyst, and a hydrogen circulation rate of about 200 to about 5,000 SCFB; said second hydrogenation conditions comprise a hydrogen partial pressure of about 800 to about 5,000 psia, a temperature of about 600F. to about 1,000F., a LHSV of about 0.1 to about 5 volumes of hydrocarbon per hour per volume of catalyst. and a hydrogen circulation rate of about 1,000 to about 25,000 SCFB; and said third hydrogenation conditions comprise a hydrogen partial pressure of about 500 to about 3,000 psia, a temperature of 450F.

1 1 to 500F., a LI-ISV of about 0.1 to about 1 volume of hydrocarbon per hour per volume of catalyst, and a hydrogen circulation rate of about 1,500 to about 15,000 SCF B.

10. The process of claim 10 wherein said first hydrogenation conditions comprise a hydrogen partial pressure of about 400 to about 2,000 psia, a temperature of about 550F. to about 800F., a Ll-ISV of about 0.25 to about 5 volumes of hydrocarbon per hour per volume of catalyst, and a hydrogen circulation rate of about 200 to about 5,000 SCFB; said second hydrogenation conditions comprise a hydrogen partial pressure of about 800 to about 5,000 psia, a temperature of about 600F. to about 1,000F., a LHSV of about 0.1 to about 5 volumes of hydrocarbon per hour per volume of catalyst, and a hydrogen circulation rate of about 1,000 to about 25,000 SCFB; and said third hydrogenation conditions comprise a hydrogen partial pressure of about 500 to about 3,000 psia, a temperature of 450F. to 500F., a Ll-ISV of about 0.1 to about 1 volume of hydrocarbon per hour per volume of catalyst, and a hydrogen circulation rate of about 1,500 to about 15,000 SCFB.

11. The process of claim '9 wherein said distillate is a solvent-extracted mineral lubricating oil distillate.

12. The process of claim wherein said distillate is a solvent-extracted mineral lubricating oil distillate.

13. The process of claim 11 wherein said solventextracted mineral lubricating oil distillate is a blend of a solvent-extracted SAE-40 oil and a solvent-extracted SAE- oil.

14. The process of claim 12 wherein said solventextracted mineral lubricating oil distillate is a blend of a solvent-extracted SAE-4O oil and a solvent-extracted SAE-20 oil.

15. In a process for producing a colorless mineral oil having good hazing properties from a mineral lubricating oil distillate wherein said distillate is contacted with a first hydrogenation catalyst comprising a metal of Group VIB of the Periodic Table of Elements and a metal of Group VIII of the Periodic Table of Elements deposed on a non-acidic or weakly-acidic support in a first hydrogenation reaction zone under first hydrogenation conditions and in the presence of hydrogen to provide a first hydrogenated product, said first hydrogenated product is contacted with a second hydrogenation catalyst comprising a metal of Group VIB of the Periodic Table of Elements and a metal of Group VIII of the Periodic Table of Elements deposed on a nonacidic or weakly-acidic support in a second hydrogenaton reaction zone under second hydrogenation conditions and in the presence of hydrogen to provide a second hydrogenated product, and said second hydrogenated product is contacted with a third hydrogenation catalyst comprising a Group VIII noble metal deposited on a non-acidic or weakly-acidic support in a third hydrogenation reaction zone under third hydrogenation conditions and in the presence of hydrogen to provide said colorless mineral oil, the improvement which comprises subjecting said first hydrogenated product to a solvent-dewaxing treatment prior to contacting it with said second hydrogenation catalyst in said second hydrogenation reaction zone.

16. The process of claim 15 wherein said solventdewaxing treatment employs a solvent comprising a mixture of an aromatic hydrocarbon and a ketone.

17. The process of claim 16 wherein said solvent is a mixture of toluene and methyl-ethyl ketone.

18. The process of claim 17 wherein the solvent-tohydrocarbon ratio that is employed in said solventdewaxing treatment ranges from about 1:1 to about 4:1.

19. The process of claim 6 wherein said first hydrogenation catalyst comprises cobalt and molybdenum on alumina, said second hydrogenation catalyst comprises nickel and molybdenum on alumina, and said third hydrogenation catalyst comprises palladium on a largepore-diameter alumina having a surface area of about 150 square meters per gram to about 500 square meters per gram and an average pore diameter of about A to about 200 A.

Q m'm'cn s'rl-a'rry P .-'\"IENT omen- "CERTIFICATEOF CORRECTION PATENI NO. 3,926,777

DATED December 16, 1975 INVENTOR(S) Roland L. Menzl H is certmed mm error appears m the above-ldennhed patent and that saad Letters Patent are hezehy corrected as shown below.

. Column 8, line 12, "remaing" should be remains 8, 32, "the" shou 1d be The 10,' 26, "LSHV" shduld be LHSV 11, 5, "claim 10" should be claim 8 Signed and Bcalcd this Eighth Day of March 1977 [SEAL] O Arrest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner ojParenrs and Trademarks 

1. A PROCESS FOR PRODUCING A COLORLESS MINERAL OIL HAVING GOOD HAZING PROPERTIES FROM A MINERAL LUBRICATING OIL DISTILLATE, WHICH PROCESS COMPRISES CONTACTING SAID DISTILLATE WITH A FIRST HYDROGENATION CATALYST COMPRISING A METAL OF GROUP VIB OF THE PERIODIC TABLE OF ELEMENTS AND A METAL OF GROUP VIII OF THE PERIODIC TABLE OF ELEMENTS DEPOSED ON A NON-ACIDIC OR WEAKLY-ACIDIC SUPPORT IN A FIRST HYDROGENATION REACTION ZONE UNDER FIRST HYDROGENATION CONDITIONS AND IN THE PRESENCE OF HYDROGEN TO OBTAIN A FIRST HYDROGENATED PRODUCT; SUBJECTING SAID FIRST HYDROGENATED PRODUCT TO A SOLVENT-DEWAXING TREATMENT TO OBTAIN A DEWAXED, HYDROGENATED PRODUCT; CONTACTING SAID DEWAXED, HYDROGENATED PRODUCT WITH A SECOND HYDROGENATION CATALYST COMPRISING A METAL OF GROUP VIB OF THE PERIODIC TABLE OF ELEMENTS AND A METAL OF GROUP VIII OF THE PERIODIC TABLE OF ELEMENTS DEPOSED ON A NON-ACIDIC OR WEAK-
 2. The process of claim 1 wherein said distillate is a solvent-extracted mineral lubricating oil distillate.
 3. The process of claim 1 wherein said distillate is a solvent-extracted and dewaxed mineral lubricating oil distillate.
 4. The process of claim 1 wherein said first hydrogenation conditions comprise a hydrogen partial pressure of about 400 to about 2,000 psia, a temperature of about 550*F. to about 800*F., a LHSV of about 0.25 to about 5 volumes of hydrocarbon per hour per volume of catalyst, and a hydrogen circulation rate of about 200 to about 5,000 SCFB; said second hydrogenation conditions comprise a hydrogen partial pressure of about 800 to about 5,000 psia, a temperature of about 600*F. to about 1,000*F., a LHSV of about 0.1 to about 5 volumes of hydrocarbon per hour per volume of catalyst, and a hydrogen circulation rate of about 1,000 to about 25,000 SCFB; and said third hydrogenation conditions comprise a hydrogen partial pressure of about 500 to about 3,000 psia, a temperature of 450*F. to 500*F., a LSHV of about 0.1 to about 1 volume of hydrocarbon per hour per volume of catalyst, and a hydrogen circulation rate of about 1,500 to about 15,000 SCFB.
 5. The process of claim 2 wherein said solvent-extracted mineral lubricating oil distillate is a blend of a solvent-extracted SAE-40 oil and a solvent-extracted SAE-20 oil.
 6. The process of claim 1 wherein said first hydrogenation catalyst and said second hydrogenation catalyst each contains about 0.5 to about 5 weight percent Group VIII metal and about 5 to about 25 weight percent Group VIB metal, calculated as the oxides and based on the total weight of the particular caTalyst, and said third hydrogenation catalyst contains about 0.1 to about 2 weight percent Group VIII noble metal, calculated as the element and based on the total weight of said third hydrogenation catalyst.
 7. The process of claim 4 wherein said distillate is a solvent-extracted mineral lubricating oil distillate.
 8. The process of claim 6 wherein said first hydrogenation catalyst and said second hydrogenation catalyst each comprise nickel and molybdenum on alumina and said third hydrogenation catalyst comprises palladium on a large-pore-diameter alumina havng a surface area of about 150 square meters per gram to about 500 square meters per gram and an average pore diameter of about 100 A to about 200 A.
 9. The process of claim 6 wherein said first hydrogenation conditions comprise a hydrogen partial pressure of about 400 to about 2,000 psia, a temperature of about 550*F. to about 800*F., a LHSV of about 0.25 to about 5 volumes of hydrocarbon per hour per volume of catalyst, and a hydrogen circulation rate of about 200 to about 5,000 SCFB; said second hydrogenation conditions comprise a hydrogen partial pressure of about 800 to about 5,000 psia, a temperature of about 600*F. to about 1,000*F., a LHSV of about 0.1 to about 5 volumes of hydrocarbon per hour per volume of catalyst, and a hydrogen circulation rate of about 1,000 to about 25,000 SCFB; and said third hydrogenation conditions comprise a hydrogen partial pressure of about 500 to about 3,000 psia, a temperature of 450*F. to 500*F., a LHSV of about 0.1 to about 1 volume of hydrocarbon per hour per volume of catalyst, and a hydrogen circulation rate of about 1,500 to about 15,000 SCFB.
 10. The process of claim 10 wherein said first hydrogenation conditions comprise a hydrogen partial pressure of about 400 to about 2,000 psia, a temperature of about 550*F. to about 800*F., a LHSV of about 0.25 to about 5 volumes of hydrocarbon per hour per volume of catalyst, and a hydrogen circulation rate of about 200 to about 5,000 SCFB; said second hydrogenation conditions comprise a hydrogen partial pressure of about 800 to about 5,000 psia, a temperature of about 600*F. to about 1,000*F., a LHSV of about 0.1 to about 5 volumes of hydrocarbon per hour per volume of catalyst, and a hydrogen circulation rate of about 1,000 to about 25,000 SCFB; and said third hydrogenation conditions comprise a hydrogen partial pressure of about 500 to about 3,000 psia, a temperature of 450*F. to 500*F., a LHSV of about 0.1 to about 1 volume of hydrocarbon per hour per volume of catalyst, and a hydrogen circulation rate of about 1,500 to about 15,000 SCFB.
 11. The process of claim 9 wherein said distillate is a solvent-extracted mineral lubricating oil distillate.
 12. The process of claim 10 wherein said distillate is a solvent-extracted mineral lubricating oil distillate.
 13. The process of claim 11 wherein said solvent-extracted mineral lubricating oil distillate is a blend of a solvent-extracted SAE-40 oil and a solvent-extracted SAE-20 oil.
 14. The process of claim 12 wherein said solvent-extracted mineral lubricating oil distillate is a blend of a solvent-extracted SAE-40 oil and a solvent-extracted SAE-20 oil.
 15. In a process for producing a colorless mineral oil having good hazing properties from a mineral lubricating oil distillate wherein said distillate is contacted with a first hydrogenation catalyst comprising a metal of Group VIB of the Periodic Table of Elements and a metal of Group VIII of the Periodic Table of Elements deposed on a non-acidic or weakly-acidic support in a first hydrogenation reaction zone under first hydrogenation conditions and in the presence of hydrogen to provide a first hydrogenated product, said first hydrogenated product is contacted with a second hydrogenation catalyst comprising a metal of Group VIB of the Periodic Table of Elements and a metal of Group VIII of the Periodic Table of Elements deposed on a non-acidic or weakly-acidic support in a second hydrogenaton reaction zone under second hydrogenation conditions and in the presence of hydrogen to provide a second hydrogenated product, and said second hydrogenated product is contacted with a third hydrogenation catalyst comprising a Group VIII noble metal deposited on a non-acidic or weakly-acidic support in a third hydrogenation reaction zone under third hydrogenation conditions and in the presence of hydrogen to provide said colorless mineral oil, the improvement which comprises subjecting said first hydrogenated product to a solvent-dewaxing treatment prior to contacting it with said second hydrogenation catalyst in said second hydrogenation reaction zone.
 16. The process of claim 15 wherein said solvent-dewaxing treatment employs a solvent comprising a mixture of an aromatic hydrocarbon and a ketone.
 17. The process of claim 16 wherein said solvent is a mixture of toluene and methyl-ethyl ketone.
 18. The process of claim 17 wherein the solvent-to-hydrocarbon ratio that is employed in said solvent-dewaxing treatment ranges from about 1:1 to about 4:1.
 19. The process of claim 6 wherein said first hydrogenation catalyst comprises cobalt and molybdenum on alumina, said second hydrogenation catalyst comprises nickel and molybdenum on alumina, and said third hydrogenation catalyst comprises palladium on a large-pore-diameter alumina having a surface area of about 150 square meters per gram to about 500 square meters per gram and an average pore diameter of about 100 A to about 200 A. 